Touch technology has progressively replaced the conventional keyboard and the mouse for inputting, and is more convenient and easier to use. A touch screen is more and more popular in the market for its user friendly features. In particular, the touch screen is prevailing in the field of smart mobile terminals.
Currently, the touch screens generally include a resistive touch screen and a capacitive touch screen. In the resistive touch screen, a touch panel is coated with a thin metallic conductive layer and a resistive layer. When the panel is touched, the thin metallic conductive layer is contacted with the resistive layer, a position of the touching event is recorded by closing a switch, and information is transmitted to a controller for further processing. In the capacitive touch screen, the touch panel is coated with a material which may store electric charges. When the panel is touched, a small amount of electric charges are accumulated at a contacted point, such electric charges are measured by circuits at each corner of the panel, and information is transmitted to a controller for processing.
In the resistive touch screen, a two-point touch is implemented by the contact of an upper inductive electrode and a lower inductive electrode; however, a multi-point touch is difficult to be implemented. In the capacitive touch screen, a multi-point touch may be implemented by a mutual capacitance between an emitting electrode and an inductive electrode. Furthermore, the touching function may be implemented without applying firm pressure on the capacitive touch screen, which is outstanding in prompt response. Thus, the capacitive touch screen is prevailing in the business market.
However, the touching has to be implemented by contacting the screen with a finger on either the resistive touch screen or the capacitive touch screen, and a non-contacted touch may not be implemented on the resistive touch screen and the capacitive touch screen.